Background: Although the reproductive calendar is the primary tool for measuring contraceptive dynamics in low-income settings, the reliability of calendar data has seldom been evaluated, primarily due to the lack of longitudinal panel data.

Methods: In this research, we evaluated the reproductive calendar using data from the Performance Monitoring for Action Project. We used population-based longitudinal data from nine settings in seven countries: Burkina Faso, Nigeria (Kano and Lagos States), Democratic Republic of Congo (Kinshasa and Kongo Central Provinces), Kenya, Uganda, Cote d’Ivoire, and India. To evaluate reliability, we compared the baseline cross-sectional report of contraceptive use (overall and by contraceptive method), nonuse, or pregnancy with the retrospective reproductive calendar entry for the corresponding month, measured at follow-up. We use multivariable regressions to identify characteristics associated with reliability or reporting.

Results: Overall, we find that the reliability of the calendar is in the “moderate/substantial” range for nearly all geographies and tests (Kappa statistics between 0.58 and 0.81). Measures of the complexity of the calendar (number of contraceptive use episodes, using the long-acting method at baseline) are associated with reliability.

Conclusions: We also find that women who were using contraception without their partners/husband’s knowledge (i.e., covertly) were less likely to report reliably in several countries.